The determination of properties of optical components has become quite important in the last few years. However, polarization effects as polarization mode dispersion (PMD) or polarization dependent loss (PDL) influence the quality of the signal transmission because the transmission rates of optical communication links were continuously enhanced. Therefore, the measurement of PMD and of PDL are well-known when characterizing optical components (see L. E. Nelson, R. M. Jopson, H. Kogelnik, “Influence of Measurement Parameters on Polarization Mode Dispersion Measurements using the Signal Delay Method”, Proc. ECOC 2000, Munich, Germany Vol. I (3.4.4), pp. 143-144 (2000); and A. Galtarossa, L. Palmieri, M. Schiano, T. Tambosso, “Improving the Accuracy of the Wavelength-Scanning Technique for PMD Measurements”, IEEE Photonics Technology Letters 12(2), pp. 184-186 (2000)). Moreover the precise measurement of polarization and the degree of polarization (DOP) are useful for compensation of PMD (see N. Kikuchi, S. Sasaki, “Polarization-Mode Dispersion (PMD) Detection Sensitivity of Degree of Polarization Method for PMD Compensation”, Proc. ECOC'99, Nice, France Vol. II (WeA1.3) pp. 8-9 (1999); and H. Rosenfeldt, R. Ulrich, U. Feiste, R. Ludwig, H. G. Weber, A. Ehrhardt, “PMD compensation in 10 Gbit-s NRZ field experiment using polarimetric error signal”, Electronics Letters 36(5), pp. 448-449 (2000)).
However, polarimeters of the prior art require a lot of beam splitters, polarizers and detectors, thereby negatively influencing the production costs of such polarimeters. In addition it is necessary to precisely adjust such components with respect to each other. An example of a polarimeter of the prior art is shown in Dennis Derickson “Fiber optic, Test and Measurement”, Prentice Hall PTR, Upper Saddle River, N.J. 07458, pp. 231-232 (1998). The polarimeter shown in this publication uses one four-way beam splitter, three linear polarizers, one quarter-wave plate and four detectors to evaluate the Stokes parameters.
EP-A-439127 discloses a fast polarization meter for measuring the polarization of a light beam by splitting it up into four beams, individually analyzing each beam, and calculating the Stokes parameter from the results. Other optical analysis devices are known e.g. from U.S. Pat. No. 5,841,536 and U.S. Pat. No. 3,927,945 (wavemeters), U.S. Pat. No. 6,052,188 (spectroscopic ellipsometer), U.S. Pat. No. 6,043,887 (polarimeter), U.S. Pat. No. 4,042,302 (broadband wavelength discriminator), or U.S. Pat. No. 4,822,169 (analyzer).
U.S. Pat. No. 4,158,506 discloses an electro-optical system for determining the polarization state of optical pulses of nanosecond durations. The output from six optical polarizers each with a different polarization is detected with six detectors, whereby the polarizations of the polarizers is selected in a way that the Stokes parameter can be directly received from the detected output signals.